Thanks for the suggestion. I tried that first and found it only gives you access to their knowledge base or their amazingly useless chatbot (called, I believe, Dolt). Neither of these was any help. There seems no way to actually provide any input to them about problems with their software. Also, the only way to talk to anybody is to be a paid customer and since all I want is the client app, I'm not one of those. An interesting model for end-user relations.
I did find though that the Apple app store has the zoom client for iPad and iPhone - just not for the iMac. Maybe Apple knows it doesn't work and so won't put it in the app store? I tried the iPad one and it seem to work. It's just not the device my wife wants to use for zoom!